Scientific Method: a series of steps to test the "validity" of a “hypothesis.” The experimentation often involves a comparison between “control” and experimental "samples.” (Brooker, G-33)
A set of assumptions, attitudes, and procedures that guide researchers in creating questions to investigate, in generating evidence, and in drawing conclusions. (Hockenbury, 15) The six steps of the scientific method include "observation" of the "phenomenon," "literature review" about the phenomenon, hypothesis development, "experimental design," “data analysis,” and "conclusion." (Norman, 5/26/09) Editor’s note - steps for the scientific method follow in order of occurrence.
Hypothesis: a suggested explanation for a set of observations that may or may not turn out to be supported. (Miell, 189) A tentative statement about the relationship between two or more variables. (Hockenbury, 15) A prediction or statement tested for verification or (disproving) by experimentation. (Collin, 341) A proposed explanation for a natural phenomenon. A proposition based on previous observations or experimental studies. A useful hypothesis must make “predictions” that can be shown to be correct or incorrect. A hypothesis is a proposed idea, while a "theory" is a broad explanation backed by extensive evidence. (Brooker, 14)
Null Hypothesis: states that any relationship between the phenomenon and the hypothesized explanation is statistically due to chance alone. To statistically support an hypothesis, you must reject the null hypothesis. (Norman, 5/26/09) A useful starting point in examining the results of a scientific investigation. It is based on the assumption that there is no significant difference between sets of observations. (Indge, 189)
Experimental Design: a procedure used to control the influence of participant "variables" in an experiment. (Cardwell, 99) A plan for collecting and utilizing data so that desired information can be obtained with sufficient precision or so that an hypothesis can be tested properly. (MeSH) A plan detailing how a study will be performed in order to represent the phenomenon under examination, to answer the research questions that have been asked, and defining the methods of data analysis. Study design is driven by research hypothesis being posed, study subject/population/sample available, logistics/resources: technology, support, networking, collaborative support, etc. (NCIt) Also referred to as ‘study design.’
Black-Box Method: a type of study where the experimenter studies the inputs and outputs (to and from the black box) and tries from the results to deduce the structure and operation of the inside of the box. (Crick-The Brain, 132)
Double Blind Study: experimental technique in which neither the participants nor the researcher interacting with the participants is aware of the group or condition to which the participants have been assigned. (Hockenbury, 31) A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment. (MeSH) A "clinical trial" in which the medical staff, the patient, and the people who analyze the results do not know the specific type of treatment the patient receives until after the clinical trial is over. (NCIt)
Placebo: an inert substance or treatment that has no known effects. (Hockenbury, 29) When used in the context of drug testing, the placebo is a preparation that has no relevant medicinal properties and is given to one group so that the medicinal effects of the real drug can be separated out from the psychological effects produced by people thinking they are receiving it. (Cardwell, 185) An inactive substance given in the place of a drug in psychological research or by physicians who wish to treat a complaint by suggestion. (Coon, 37)
Placebo Effect: changes in behavior due to expectations that a drug (or other treatment) will have some effect. (Coon, 37) Occurs when an individual has a psychological and physiological reaction to what is actually a fake treatment or drug. (Hockenbury, 184) Also referred to as ‘placebo response.'
Sample: a selected segment of a population used to represent the group that is being studied; a subset of a population. (Hockenbury, G-12) A subset of a larger population, selected for investigation to draw conclusions or make estimates about the larger population. (NCIt) (Used for) studies in which a number of subjects are selected from all subjects in a defined population. Conclusions based on sample results may be attributed only to the population sampled. (MeSH)
Control: the sample in an experiment that is treated just like an experimental sample except that it is not subjected to one particular variable. (Brooker, G-9) In an experiment, the group of participants who are exposed to all experimental conditions, except the "independent variable" (or treatment of interest); the group against which changes in the "experimental group" are compared. (Hockenbury, G-3) Also referred to as 'control sample' and 'control group.'
Negative Control: in an experiment, includes the substance that does not contain the compound you are testing. (Norton Labs, 27)
Positive Control: in an experiment, includes the substance being tested for such that it will always yield positive results for that compound. Positive and negative controls give you a standard of comparison for the substances you are testing. When in doubt about results, you can compare the substance being tested to both the positive and the negative control and determine which one your sample is most like. In addition, the controls will help indicate whether the "reagent" is working properly. (Norton Labs, 27) When testing 'qualitative' data, a positive control is a test that will always yield positive results, a negative control is a test that will always yield negative results. (Norman, 5/26/09)
Experimental Sample: the sample in an experiment that is subjected to some type of variation that does not occur for the “control sample.” (Brooker, G-14) Also referred to as 'experimental group.'
Representative Sample: a small, randomly selected part of a larger population that accurately reflects characteristics of the whole population. (Coon, 41)
Sample Size: the number of individuals receiving either an experimental or a control treatment, for an experiment. (Norman, 14) The number of subjects required for primary analysis. Also, the number of subjects in a clinical trial. (NCIt) In order to be statistically acceptable, a large sample must be tested. (Norman, 5/26/09) The number of units (persons, animals, patients, specified circumstances, etc.) in a population to be studied. The sample size should be big enough to have a high likelihood of detecting a true difference between two groups. (MeSH)
Single Blind Study: one in which the researchers, but not the subjects, are aware of critical information. (Hockenbury, 31) A method in which either the observer(s) or the subject(s) is kept ignorant of the group to which the subjects are assigned. (MeSH) A type of clinical trial in which only the doctor knows whether a patient is taking the standard treatment or the new treatment being tested. This helps prevent bias in treatment studies. (NCIt)
Data Collection: systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data. (MeSH)
Literature Review: past accounts of the experiment or factors that may affect it based on real scientific observation or sound scientific knowledge. (Norman Lab, 13) Examination of published material on a subject. It may be comprehensive to various degrees and the time range of material scrutinized may be broad or narrow, but the reviews most often desired are reviews of the current literature. The textual material examined may be equally broad and can encompass, in medicine specifically, clinical material as well as experimental research or case reports. (MeSH)
Observation: occurrence of a phenomenon should be more than once, noting the surrounding environment or circumstance. If experimenting on a theoretical question, it should be something that can be tested through experimentation. (Norman Labs, 13) The act of regarding attentively and studying facts and occurrences, gathering data through analyzing, measuring, and drawing conclusions, with the purpose of applying the observed information to theoretical assumptions. Observation as a scientific method in the acquisition of knowledge began in classical antiquity; in modern science and medicine its greatest application is facilitated by modern technology. Observation is one of the components of the research process. (MeSH)
Data Analysis: once observations have been made and measurements have been collected, the raw data needs to be summarized and analyzed. Researchers use "statistics" to summarize, analyze, and draw conclusions about the data. (Hockenbury, 17)
Conclusion: the end, finish, or termination of a speech, writing, etc.; especially a final section summarizing the main points. (Oxford) Briefly summarizes the (hypothesis) and the main points … without using the exact same words and sentences. (Cordray, 11) A position or opinion or judgment reached after consideration. (NCIt)
Speculation: the action of speculating or theorizing; abstract or hypothetical reflection or meditation; conjecture; surmise. Also, a theory, work, etc., reached by speculating. (Oxford) The best research emerges from a dialectic between speculation and healthy skepticism. (Ramachandran, xv,xvi)